wash down/live well

[WaxedElvis]

Wash down/live well pump works intermittently on the water. I can hear it running on the trailer. Do these thing loose their prime some how? Should I turn the pump off when switching the valve from live well to wash down? It doesn't appear to be electrical as the pump seems to run when switched on. I'm not too proud to admit this very well could be operator error of some sort. Could the pump just be bad?